Improving broiler performance at market age regardless of stocking density by using a pre-starter diet

Evaluating broiler welfare and behavior as affected by growth rate and stocking density

This study evaluated the welfare and behaviors of Cobb 700 broilers as affected by growth rate (GR) and stocking density (SD). Slower-growth (weight gain < 50 g/d) and medium-growth (weight gain = 50-60 g/d) broilers were produced by providing 57.1% and 78.6% of the feed intake listed in the Cobb 700 production manual for standard (fed ad libitum) broilers (weight gain > 60 g/d). Broilers at all 3 GRs were reared at 2 SDs of 30 and 40 kg/m2. Broiler welfare indicators, including gait score, tibia strength, feather coverage, and footpad condition were evaluated when birds reached 1, 2, and 3 kg of body weight. The activity index was determined by overhead cameras and image processing, and the time spent at feeders was recorded using the radio-frequency identification (RFID) systems. The results show that it took 45 d for standard, 52 d for medium-growth, and 62 d for slower-growth broilers to reach a 3 kg market body weight. Feed conversion ratios (FCR, kg/kg) were 1.57 for standard, 1.67 for medium-growth, and 1.80 for slower-growth broilers. Growth rate and SD had an interaction effect on feather cleanliness (P = 0.03), and belly feather coverage (P = 0.02). Slower-growth broilers were more active and had better feather coverage and gait scores than medium-growth and standard broilers (all P < 0.01) but may feel hungry and depressed, medium-growth broilers spent the most time at the feeder among the 3 growth groups (P = 0.02), and standard broilers showed the best production performance. Broilers at 30 kg/m2 showed better bone strength (P = 0.04), and footpad condition (P < 0.01) compared to those at 40 kg/m2. In conclusion, reducing GR and SD may slightly improve broiler leg health at the high expense of compromised production performance and prolonged production cycles.

Effect of housing system and housing density on performance, viability, and gastrointestinal tract growth of broiler chicks during the first 2 wk of age

This experiment was conducted to study the effect of housing systems and housing densities on the performance and digestive tract growth of broiler chicks during the first 2 wk of age. A total of 3,600 Cobb500 day-old chicks were stocked at 4 densities (30, 60, 90, and 120 chicks/m2), and reared under 2 housing systems (conventional housing system and newly developed housing system), yielding a 2 × 4 factorial arrangement. The studied traits were performance, viability, and gastrointestinal tract development. The results indicated that housing systems and housing densities significantly (P < 0.001) affected the performance and GIT development of chicks. There were no significant interactions between housing system and housing density for body weight, body weight gain, feed intake, and feed conversion. The results also showed that the effects of housing density were age-dependent. That is, the higher the density, the lower the performance and digestive tract growth with advancing age. In conclusion, birds in the conventional system outperformed birds in the newly developed housing system, and further work is needed to improve the new housing system. To achieve the highest performance, digestive tract growth, and digesta content, a density of 30 chicks/m2 is recommended for chicks up to 14-days old.